分组 <anonymous type:, string> 不包含“”的定义，也没有扩展方法“”

Question

Goal : Group by 2 columns

Error : This causes the error IGrouping does not contain a definition for 'Sub_ID' and no extension method 'SubID' accepting a first argument of type IGrouping

Code :

return db.View.Where(m => m.Mem_ID == Some_MemID && m.Last_Name.ToLower() == Search_MemLastName.ToLower()).GroupBy(t => new { t.Sub_ID, t.Mem_Seq }).OrderBy(t => t.Subs_ID);

I've also tried adding .key but that did not help. Did not find a solution in How to order IGrouping without changing its type? or IGrouping does not contain a definition for

Been looking at this for hours

Answer 1

You are sorting the groups, and you have to access the grouped property(ies) through the Key :

.OrderBy(t => t.Key.Subs_ID)

Edit: If you only want to display distinct elements by Sub_ID , add .Select(x => x.First()) to select only the top result per group:

return db.View
    .Where(m => m.Mem_ID == Some_MemID && m.Last_Name.ToLower() == Search_MemLastName.ToLower())
    .GroupBy(t => new { t.Sub_ID, t.Mem_Seq })
    .OrderBy(g => g.Key.Subs_ID)
    .Select(g => g.First());

With GroupBy you transformed an IQueryable<T> into an IGrouping<TKey, T> . The last Select is to reduce the groupings back to single elements.